Pub Date : 2026-01-03DOI: 10.1016/j.optcom.2026.132871
Wenhui Zhu , Jun Zhao , Jianxu Liu , Daxing Dong , Yangyang Fu , Youwen Liu
Recent studies on circularly polarized light detection via metasurfaces have attracted considerable interest. Phase-change materials exhibit exceptional active tunability, showing significant promise for optoelectronic integrated detectors. In this paper, a dynamically tunable transmissive metasurface waveplate based on Sb2S3 phase-change material is designed, which achieves reversible phase transitions for straightforward elliptically polarized light detection. By combining the known phase difference modulation depth with the information of the outgoing linearly polarized light electric field, the polarization angle (ψ) and ellipticity angle (χ) of the incident light can be determined. The handedness of the light can be determined from the sign of the phase retardance difference. This method expands the design flexibility of polarization-dependent metasurfaces and offers a novel solution for straightforward elliptically polarized light detection.
{"title":"Dynamically tunable metasurface waveplate for straightforward detection of elliptical polarization","authors":"Wenhui Zhu , Jun Zhao , Jianxu Liu , Daxing Dong , Yangyang Fu , Youwen Liu","doi":"10.1016/j.optcom.2026.132871","DOIUrl":"10.1016/j.optcom.2026.132871","url":null,"abstract":"<div><div>Recent studies on circularly polarized light detection via metasurfaces have attracted considerable interest. Phase-change materials exhibit exceptional active tunability, showing significant promise for optoelectronic integrated detectors. In this paper, a dynamically tunable transmissive metasurface waveplate based on Sb<sub>2</sub>S<sub>3</sub> phase-change material is designed, which achieves reversible phase transitions for straightforward elliptically polarized light detection. By combining the known phase difference modulation depth with the information of the outgoing linearly polarized light electric field, the polarization angle (<em>ψ</em>) and ellipticity angle (<em>χ</em>) of the incident light can be determined. The handedness of the light can be determined from the sign of the phase retardance difference. This method expands the design flexibility of polarization-dependent metasurfaces and offers a novel solution for straightforward elliptically polarized light detection.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"605 ","pages":"Article 132871"},"PeriodicalIF":2.5,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145898016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-31DOI: 10.1016/j.optcom.2025.132858
Hanwei Cheng , Wenjian Wang , Yihua Dong , Rui Yan , Nauman Ali , Sha An , Juanjuan Zheng , Peng Gao , Xiaofang Wang , Tanping Li , Kai Wen , Peng Gao
In this work, we propose a novel method for simultaneously measuring the thickness and refractive index (RI) of transparent samples based on dual-wavelength on-axis digital holography. A sample under test is rotated from 0° to 20° with an interval of 1°, and three-step phase-shifting holograms are recorded for each rotation angle. For each wavelength, a phase-versus-angle response curve is constructed from a series of hologram rotations, then fitted with a physical model to determine the thickness and RI of the sample. This method features a high RI and thickness measurement precision of ∼5 × 10−5 and 1 × 10−2, and a high stability of 3.7 × 10−5 over a period of 5 min. Combining dual-wavelength data and the Cauchy dispersion formula, RI at any wavelength within the visible spectral range can be predicted. We can envisage that the proposed technique will find widespread application in related industries, such as morphology measurement.
{"title":"Simultaneous refractive index and thickness measurement based on dual-wavelength digital holography","authors":"Hanwei Cheng , Wenjian Wang , Yihua Dong , Rui Yan , Nauman Ali , Sha An , Juanjuan Zheng , Peng Gao , Xiaofang Wang , Tanping Li , Kai Wen , Peng Gao","doi":"10.1016/j.optcom.2025.132858","DOIUrl":"10.1016/j.optcom.2025.132858","url":null,"abstract":"<div><div>In this work, we propose a novel method for simultaneously measuring the thickness and refractive index (RI) of transparent samples based on dual-wavelength on-axis digital holography. A sample under test is rotated from 0° to 20° with an interval of 1°, and three-step phase-shifting holograms are recorded for each rotation angle. For each wavelength, a phase-versus-angle response curve is constructed from a series of hologram rotations, then fitted with a physical model to determine the thickness and RI of the sample. This method features a high RI and thickness measurement precision of ∼5 × 10<sup>−5</sup> and 1 × 10<sup>−2</sup>, and a high stability of 3.7 × 10<sup>−5</sup> over a period of 5 min. Combining dual-wavelength data and the Cauchy dispersion formula, RI at any wavelength within the visible spectral range can be predicted. We can envisage that the proposed technique will find widespread application in related industries, such as morphology measurement.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"605 ","pages":"Article 132858"},"PeriodicalIF":2.5,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145929150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Multi-focal-length metalens shows broad application prospects in compact three-dimensional imaging and near-eye display, yet their performance is significantly constrained by inter-focal crosstalk and low fill factor. This paper proposes a multi-focal-length square-annular metalens (MFLSAM) to address these challenges. By introducing the Chebyshev distance, the design transforms the arrangement of metaatoms into square-annular symmetry, achieving a 100 % fill factor. Finite-Difference Time-Domain simulations demonstrate that the energy distribution between the dual foci of the MFLSAM can be effectively controlled by adjusting the radial partition ratio. When ratio is 0.60, the electric field intensity of the two foci are nearly balanced (15.49 V/m and 15.63 V/m), with full width at half maximum (FWHM) values of 500 nm and 535 nm, respectively, indicating excellent focusing performance and energy balance. A MFLSAM with a diameter of 5 mm and focal lengths of 3 mm and 6 mm was fabricated using high-precision electron-beam lithography, with structural dimensional errors below 5 %. The measured FWHM values of the dual foci are 657 ± 2 nm and 751 ± 2 nm, significantly superior to the 760 ± 2 nm and 905 ± 2 nm of the traditional circular design, effectively suppressing inter-focal crosstalk. Furthermore, AR imaging tests confirmed that the fabricated MFLSAM can achieve clear, low-crosstalk display performance at both focal planes, validating its potential for applications in high-performance augmented reality near-eye displays.
{"title":"High-efficiency and low-crosstalk multi-focal-length metalens via a square-annular structure for near-eye displays","authors":"Chunliang Chen , Yuyan Peng , Xiongtu Zhou , Yongai Zhang , Tailiang Guo , Yuhua Qin","doi":"10.1016/j.optcom.2025.132861","DOIUrl":"10.1016/j.optcom.2025.132861","url":null,"abstract":"<div><div>Multi-focal-length metalens shows broad application prospects in compact three-dimensional imaging and near-eye display, yet their performance is significantly constrained by inter-focal crosstalk and low fill factor. This paper proposes a multi-focal-length square-annular metalens (MFLSAM) to address these challenges. By introducing the <em>Chebyshev</em> distance, the design transforms the arrangement of metaatoms into square-annular symmetry, achieving a 100 % fill factor. Finite-Difference Time-Domain simulations demonstrate that the energy distribution between the dual foci of the MFLSAM can be effectively controlled by adjusting the radial partition ratio. When ratio is 0.60, the electric field intensity of the two foci are nearly balanced (15.49 V/m and 15.63 V/m), with full width at half maximum (FWHM) values of 500 nm and 535 nm, respectively, indicating excellent focusing performance and energy balance. A MFLSAM with a diameter of 5 mm and focal lengths of 3 mm and 6 mm was fabricated using high-precision electron-beam lithography, with structural dimensional errors below 5 %. The measured FWHM values of the dual foci are 657 ± 2 nm and 751 ± 2 nm, significantly superior to the 760 ± 2 nm and 905 ± 2 nm of the traditional circular design, effectively suppressing inter-focal crosstalk. Furthermore, AR imaging tests confirmed that the fabricated MFLSAM can achieve clear, low-crosstalk display performance at both focal planes, validating its potential for applications in high-performance augmented reality near-eye displays.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"605 ","pages":"Article 132861"},"PeriodicalIF":2.5,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145929155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-31DOI: 10.1016/j.optcom.2025.132859
Maoni Chen , Jianqiu Cao , Min Fu , Yangmei Sun , Shangde Zhou , Qi Zhang , Aimin Liu , Zilun Chen , Zhihe Huang , Zefeng Wang , Jinbao Chen
The short-tapered fiber for mode field adaptation from single-mode fiber to large-core highly-multimode fiber is investigated. Two sorts of tapered highly-multimode fibers (taper ratio close to 5:1) with core diameters of 50 μm and 105 μm are designed and tested. By using only 0.5-cm taper length, the adiabatic transmission of the fundamental mode into the 50-μm core fiber was achieved, and the M2 factor is about 1.2. Moreover, by using the taper length as short as about 5 cm, the fundamental mode transmission can also be well maintained into the 105-μm core fiber and the M2 factor of 1.49 can be achieved, which should be the first demonstration that short-tapered fiber can preserve near-diffraction-limited beam quality transmission into highly-multimode fiber with the core diameter exceeding 100 μm. Besides, it is also revealed that keeping the linear taper shape is of great importance for adiabatic transmission of the fundamental mode into a highly-multimode fiber. The pertinent study can provide significant guidance for the design and application of the short-tapered large-core highly-multimode fiber.
{"title":"Short-tapered fiber for mode field adaptation from single-mode fiber to large-core highly-multimode fiber","authors":"Maoni Chen , Jianqiu Cao , Min Fu , Yangmei Sun , Shangde Zhou , Qi Zhang , Aimin Liu , Zilun Chen , Zhihe Huang , Zefeng Wang , Jinbao Chen","doi":"10.1016/j.optcom.2025.132859","DOIUrl":"10.1016/j.optcom.2025.132859","url":null,"abstract":"<div><div>The short-tapered fiber for mode field adaptation from single-mode fiber to large-core highly-multimode fiber is investigated. Two sorts of tapered highly-multimode fibers (taper ratio close to 5:1) with core diameters of 50 μm and 105 μm are designed and tested. By using only 0.5-cm taper length, the adiabatic transmission of the fundamental mode into the 50-μm core fiber was achieved, and the M<sup>2</sup> factor is about 1.2. Moreover, by using the taper length as short as about 5 cm, the fundamental mode transmission can also be well maintained into the 105-μm core fiber and the M<sup>2</sup> factor of 1.49 can be achieved, which should be the first demonstration that short-tapered fiber can preserve near-diffraction-limited beam quality transmission into highly-multimode fiber with the core diameter exceeding 100 μm. Besides, it is also revealed that keeping the linear taper shape is of great importance for adiabatic transmission of the fundamental mode into a highly-multimode fiber. The pertinent study can provide significant guidance for the design and application of the short-tapered large-core highly-multimode fiber.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"604 ","pages":"Article 132859"},"PeriodicalIF":2.5,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-31DOI: 10.1016/j.optcom.2025.132857
Dalya H. Abbas , Hanan J. Taher , Bushra R. Mahdi
This research delineates the advancement of a modern optical photodetector. It was essential to polish the H-shaped plastic optical fiber photodetector (HPOFPD) so that it could be used in surface plasmon resonance (SPR) phenomena. The first electrode of the detector is made up of thin silver layers. Then, a nano-graphene oxide (NGO) layer and a nano-gold layer are added. Together, these layers define the active area of the photodetector, which increases light absorption and improves the efficiency of photoelectric conversion. Then, the next layer of the NGO is put in place. Next, a silver layer is put on the second electrode. The detector is tested to see how well it works. The results show that the photodetector is more sensitive across a range of visible wavelengths, reacts faster, and converts light to electricity more efficiently. These features show that this type of photodetector is used in electrical applications, environmental sensors, and optical communication systems. This study demonstrates that the integration of nanomaterials with optical fibers can significantly enhance the performance of photodetectors, thereby promoting the advancement of innovative and more efficient optical sensors.
The detector's responsivity is about 2.3 × 103 (A/W) at a wavelength of 550 nm, and its external quantum efficiency (E.Q.E.) is 5.1 × 105 %. The average time it took to rise and recover was 1.3 ms and 2.016667 ms, respectively. The average reaction time is 3.316667 ms, the detectability is 620.04 × 1015 W, and the standard measurement is 787.60 × 1019 MHz−1/2 W. The results showed that the photodetector is more sensitive to different wavelengths of light in the visible spectrum, reacts more quickly, and converts optical energy to electrical energy more efficiently.
{"title":"H-shape of high-response surface plasmon resonance fiber optic detectors","authors":"Dalya H. Abbas , Hanan J. Taher , Bushra R. Mahdi","doi":"10.1016/j.optcom.2025.132857","DOIUrl":"10.1016/j.optcom.2025.132857","url":null,"abstract":"<div><div>This research delineates the advancement of a modern optical photodetector. It was essential to polish the H-shaped plastic optical fiber photodetector (HPOFPD) so that it could be used in surface plasmon resonance (SPR) phenomena. The first electrode of the detector is made up of thin silver layers. Then, a nano-graphene oxide (NGO) layer and a nano-gold layer are added. Together, these layers define the active area of the photodetector, which increases light absorption and improves the efficiency of photoelectric conversion. Then, the next layer of the NGO is put in place. Next, a silver layer is put on the second electrode. The detector is tested to see how well it works. The results show that the photodetector is more sensitive across a range of visible wavelengths, reacts faster, and converts light to electricity more efficiently. These features show that this type of photodetector is used in electrical applications, environmental sensors, and optical communication systems. This study demonstrates that the integration of nanomaterials with optical fibers can significantly enhance the performance of photodetectors, thereby promoting the advancement of innovative and more efficient optical sensors.</div><div>The detector's responsivity is about 2.3 × 10<sup>3</sup> (A/W) at a wavelength of 550 nm, and its external quantum efficiency (E.Q.E.) is 5.1 × 10<sup>5</sup> %. The average time it took to rise and recover was 1.3 ms and 2.016667 ms, respectively. The average reaction time is 3.316667 ms, the detectability is 620.04 × 10<sup>15</sup> W, and the standard measurement is 787.60 × 10<sup>19</sup> MHz<sup>−1/2</sup> W. The results showed that the photodetector is more sensitive to different wavelengths of light in the visible spectrum, reacts more quickly, and converts optical energy to electrical energy more efficiently.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"604 ","pages":"Article 132857"},"PeriodicalIF":2.5,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-30DOI: 10.1016/j.optcom.2025.132852
Jianglian Wang, Atsushi Okamoto
We propose a depth-multiplexed holographic display based on spatial region repositioning that expands the effective display area under the intrinsic space–bandwidth product (SBP) limitation of a single spatial light modulator (SLM). Unlike conventional multi-plane holographic displays, which reconstruct different content at distinct axial depths, our approach partitions a large target image into distinct spatial regions, with each region corresponding to a specific axial depth. A compact beam-splitter assembly then optically repositions these depth-multiplexed regions onto the same observation plane, yielding a single enlarged display while still employing a single SLM. The results of numerical simulations and optical experiments verify that the proposed method significantly enlarges the area for both two- and three-dimensional holographic displays. In contrast to conventional approaches that expand the area by increasing the physical modulation aperture or by integrating multiple synchronized SLMs and customized diffractive elements, the proposed method offers a compact and practical solution for large-area holographic displays.
{"title":"Large-area holographic display by depth-multiplexed spatial region repositioning on a single spatial light modulator","authors":"Jianglian Wang, Atsushi Okamoto","doi":"10.1016/j.optcom.2025.132852","DOIUrl":"10.1016/j.optcom.2025.132852","url":null,"abstract":"<div><div>We propose a depth-multiplexed holographic display based on spatial region repositioning that expands the effective display area under the intrinsic space–bandwidth product (SBP) limitation of a single spatial light modulator (SLM). Unlike conventional multi-plane holographic displays, which reconstruct different content at distinct axial depths, our approach partitions a large target image into distinct spatial regions, with each region corresponding to a specific axial depth. A compact beam-splitter assembly then optically repositions these depth-multiplexed regions onto the same observation plane, yielding a single enlarged display while still employing a single SLM. The results of numerical simulations and optical experiments verify that the proposed method significantly enlarges the area for both two- and three-dimensional holographic displays. In contrast to conventional approaches that expand the area by increasing the physical modulation aperture or by integrating multiple synchronized SLMs and customized diffractive elements, the proposed method offers a compact and practical solution for large-area holographic displays.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"604 ","pages":"Article 132852"},"PeriodicalIF":2.5,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-30DOI: 10.1016/j.optcom.2025.132856
Priyanka Das
This work presents a comprehensive study on harmonic beam steering and vortex OAM generation using space-time coded metasurfaces at THz frequencies by demonstrating the design and implementation of 1-bit and 2-bit graphene-based coded metasurfaces, by showcasing their capabilities in beam steering, gain enhancement and OAM modulation. The theoretical framework is supported by rigorous simulations and radiation pattern analyses, highlighting the potential for dynamic wavefront control in THz applications. Space-time-coding (STC) metasurfaces disrupt reciprocity and create new possibilities for manipulating harmonic beams. A single bit coded metasurface unit cell is designed on Quartz (SiO2) substrate at 7 THz by leveraging the variation of graphene potential. A single bit and double bit coded metasurface are designed for second order OAM modulation. A double bit coded metasurface on SiO2 substrate is designed to realize harmonic beam steering at 5.9 THz. Two-bit coded metasurfaces with Fourier and helical phase distribution are used for beamsteering at 30° and 45°. A 2-bit coded radial gradient metasurface is designed for gain enhancement. Harmonic beamforming capabilities are obtained by adjusting the reflection phase and magnitude distribution on the metasurface by providing each unit cell with proper periodic time sequences. The time-varying coding sequence is used to produce harmonic frequencies in various main beam directions. Harmonic beamsteering facilitates the realization of multi-bit configurable phases using a double bit binary-coded metasurface in the time domain. Higher order space-time equivalent phases can be used to achieve better sensing, greater resolution imaging and improved wireless communications at THz frequencies.
{"title":"Harmonic beam steering and vortex OAM generation by space-time coded metasurface at THz frequencies","authors":"Priyanka Das","doi":"10.1016/j.optcom.2025.132856","DOIUrl":"10.1016/j.optcom.2025.132856","url":null,"abstract":"<div><div>This work presents a comprehensive study on harmonic beam steering and vortex OAM generation using space-time coded metasurfaces at THz frequencies by demonstrating the design and implementation of 1-bit and 2-bit graphene-based coded metasurfaces, by showcasing their capabilities in beam steering, gain enhancement and OAM modulation. The theoretical framework is supported by rigorous simulations and radiation pattern analyses, highlighting the potential for dynamic wavefront control in THz applications. Space-time-coding (STC) metasurfaces disrupt reciprocity and create new possibilities for manipulating harmonic beams. A single bit coded metasurface unit cell is designed on Quartz (SiO<sub>2</sub>) substrate at 7 THz by leveraging the variation of graphene potential. A single bit and double bit coded metasurface are designed for second order OAM modulation. A double bit coded metasurface on SiO<sub>2</sub> substrate is designed to realize harmonic beam steering at 5.9 THz. Two-bit coded metasurfaces with Fourier and helical phase distribution are used for beamsteering at 30° and 45°. A 2-bit coded radial gradient metasurface is designed for gain enhancement. Harmonic beamforming capabilities are obtained by adjusting the reflection phase and magnitude distribution on the metasurface by providing each unit cell with proper periodic time sequences. The time-varying coding sequence is used to produce harmonic frequencies in various main beam directions. Harmonic beamsteering facilitates the realization of multi-bit configurable phases using a double bit binary-coded metasurface in the time domain. Higher order space-time equivalent phases can be used to achieve better sensing, greater resolution imaging and improved wireless communications at THz frequencies.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"604 ","pages":"Article 132856"},"PeriodicalIF":2.5,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have proposed and fabricated a vertical cavity surface emitting laser (VCSEL) with two independently controllable contacts. By directly etching a trench in the p-type doped distributed Bragg reflector (DBR), we created two sub-mesa structures above the oxide layer that can be independently modulated by RF signal, without degrading the modulation capability of the device. Under optimized conditions of mesa diameter, trench depth, trench offset, and specific current combinations, a -3dB bandwidth of over 30 GHz can be achieved. Moreover, this structure enables independent multi-channel modulation of the two adjacent sub-mesas for ultra-high-speed data transmission exceeding 100 Gbps using PAM4 signaling. Therefore, this is a feasible structural design for achieving multi-channel signal transmission using a single VCSEL. Compared with traditional VCSEL array. it can reduce the array footprint while achieving high-speed transmission. It holds great promise for highly integrated transmission arrays and represents an important step toward realizing next-generation fiber-optic communication systems with high energy efficiency.
{"title":"Vertical-cavity surface-emitting lasers with two controllable independent modulation cavities","authors":"Zhongmin He, Chuyu Zhong, Jian Feng, Shaochi Pan, Zhenhuan Qiu, Yichun Chen, Xing Zhang, Wei Miao, Bin Wang, Shihao Ding, Shupeng Deng, Nannan Li, Jinlong Lu, Hui Li","doi":"10.1016/j.optcom.2025.132855","DOIUrl":"10.1016/j.optcom.2025.132855","url":null,"abstract":"<div><div>We have proposed and fabricated a vertical cavity surface emitting laser (VCSEL) with two independently controllable contacts. By directly etching a trench in the p-type doped distributed Bragg reflector (DBR), we created two sub-mesa structures above the oxide layer that can be independently modulated by RF signal, without degrading the modulation capability of the device. Under optimized conditions of mesa diameter, trench depth, trench offset, and specific current combinations, a -3dB bandwidth of over 30 GHz can be achieved. Moreover, this structure enables independent multi-channel modulation of the two adjacent sub-mesas for ultra-high-speed data transmission exceeding 100 Gbps using PAM4 signaling. Therefore, this is a feasible structural design for achieving multi-channel signal transmission using a single VCSEL. Compared with traditional VCSEL array. it can reduce the array footprint while achieving high-speed transmission. It holds great promise for highly integrated transmission arrays and represents an important step toward realizing next-generation fiber-optic communication systems with high energy efficiency.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"604 ","pages":"Article 132855"},"PeriodicalIF":2.5,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-30DOI: 10.1016/j.optcom.2025.132854
Yina Dai , Wang Zhao , Shuai Wang , Hongli Guan , Han Guo , Shenghu Liu , Fangfang Chai , Yaping Li , Ping Yang
The scintillation caused by atmosphere turbulence results in drastic fluctuations in the intensity and signal-to-noise ratio (SNR) of the spot-array image and influences measurement precision of the Shack-Hartmann wavefront sensor seriously. In this paper, we propose a kind of spot centroid tracking method based on Kalman filtering. An independent Kalman model for each sub-aperture is established by utilizing the spot centroid information of previous multi-frame images. With the Kalman models, we can track each spot and predict its current estimated position which is used as the window center for extracting spot image data as well as centroid calculation. The advantage of this method is to use historical centroid information to find the current spot area even though the spot is submerged by noise. Simulations and experiments were conducted to validate the effectiveness of the proposed method. Under different degrees of scintillation, this method demonstrates superior wavefront reconstruction stability and achieves obvious improvement (about 23 %–65 %) in wavefront reconstruction accuracy compared to other algorithms.
{"title":"Spot centroid tracking for Shack-Hartmann wavefront sensor based on Kalman filtering","authors":"Yina Dai , Wang Zhao , Shuai Wang , Hongli Guan , Han Guo , Shenghu Liu , Fangfang Chai , Yaping Li , Ping Yang","doi":"10.1016/j.optcom.2025.132854","DOIUrl":"10.1016/j.optcom.2025.132854","url":null,"abstract":"<div><div>The scintillation caused by atmosphere turbulence results in drastic fluctuations in the intensity and signal-to-noise ratio (SNR) of the spot-array image and influences measurement precision of the Shack-Hartmann wavefront sensor seriously. In this paper, we propose a kind of spot centroid tracking method based on Kalman filtering. An independent Kalman model for each sub-aperture is established by utilizing the spot centroid information of previous multi-frame images. With the Kalman models, we can track each spot and predict its current estimated position which is used as the window center for extracting spot image data as well as centroid calculation. The advantage of this method is to use historical centroid information to find the current spot area even though the spot is submerged by noise. Simulations and experiments were conducted to validate the effectiveness of the proposed method. Under different degrees of scintillation, this method demonstrates superior wavefront reconstruction stability and achieves obvious improvement (about 23 %–65 %) in wavefront reconstruction accuracy compared to other algorithms.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"605 ","pages":"Article 132854"},"PeriodicalIF":2.5,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145929065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Single-pixel imaging (SPI), as a low-cost, high-sensitivity imaging technique based on compressive sensing theory, demonstrates broad application prospects. Deep learning-based reconstruction has been recognized as an effective approach for achieving fast and high-quality reconstruction. Nevertheless, existing deep learning reconstruction networks for SPI are typically designed for fixed sampling rates, resulting in redundant model storage and the need for repeated training. To address this issue, this paper proposes a multi-sampling rate compressed reconstruction network (MSRCR-Net) that integrates both model-driven and data-driven strategies. Inspired by sequential learning, the network incorporates a hidden state mechanism and dense connections, enabling multi-sampling rate reconstruction with a single model. A staged optimization strategy is employed to jointly optimize the sampling matrix and the reconstruction process. Experimental results demonstrate that compared with prominent existing reconstruction methods, MSRCR-Net achieves greater reconstruction performance but with fewer parameters. Additionally, its practicality and superiority are validated through a single-photon counting SPI microscopic imaging system.
{"title":"Multi-sampling-rate compressed reconstruction network driven by joint model and data for single pixel imaging","authors":"Xule Dai, Qiurong Yan, Xinhong Luo, Guo Lu, Junyuan Yin, Xin Huang","doi":"10.1016/j.optcom.2025.132853","DOIUrl":"10.1016/j.optcom.2025.132853","url":null,"abstract":"<div><div>Single-pixel imaging (SPI), as a low-cost, high-sensitivity imaging technique based on compressive sensing theory, demonstrates broad application prospects. Deep learning-based reconstruction has been recognized as an effective approach for achieving fast and high-quality reconstruction. Nevertheless, existing deep learning reconstruction networks for SPI are typically designed for fixed sampling rates, resulting in redundant model storage and the need for repeated training. To address this issue, this paper proposes a multi-sampling rate compressed reconstruction network (MSRCR-Net) that integrates both model-driven and data-driven strategies. Inspired by sequential learning, the network incorporates a hidden state mechanism and dense connections, enabling multi-sampling rate reconstruction with a single model. A staged optimization strategy is employed to jointly optimize the sampling matrix and the reconstruction process. Experimental results demonstrate that compared with prominent existing reconstruction methods, MSRCR-Net achieves greater reconstruction performance but with fewer parameters. Additionally, its practicality and superiority are validated through a single-photon counting SPI microscopic imaging system.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"604 ","pages":"Article 132853"},"PeriodicalIF":2.5,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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